Attachment to spark-plugs.



H. G. HEMMETER. ATTACHMENT T0 SPARK PLUGS.

APPLICATION FILED APR 27, I911.

Patented Apr. 2, 1912.

awe/"43oz ifs/wry C. #01207 e/er Wvkmmom UNITED STAS PATENT QFFICE.

HENRY C. HEMMETER, OF PONTIAC, MICHIGAN, ASSIGNOR 0F ONE-HALF T0 CASSIUSC. VAN WAGONER, OF PONTIAC, MICHIGAN.

ATTACHMENT TO SPARK-PLUGS.

Specification of Letters Patent.

Application filed April 27, 1911.

Patented Apr. 2, 1912.

Serial No. 623,589.

To all whom it may concern:

Be'it known that I, HENRY C. HEMMETER, a citizen of the United States ofAmerica, residing at Pontiac, in the county of Oakland and State ofMichigan, have invented certain new and useful Improvements inAttachments to Spark-Plugs, of which the following is a specification,reference being had therein to the accompanying drawings.

This inv ention refers to an attachment to spark plug adapted to connectthe ordinary jump spark plug into a double jump spark plug, and theinvention consists in the construction, arrangement and combination ofparts more fully described hereinafter and shown in the accompanyingdrawings, in which- Figure 1 is a vertical central section of tion witha spark plug of conventional form and shown in elevation; Fig. 2 is atop plan view of the attachment, and Fig. 3 is a horizontal section online (0-00 of Fig. 1.

Referring to the drawings 1 and 2 are plates of insulating material,spaced apart a transverse shell 3, consisting prefer-- ably of a sectionof glass tubing; 4, 4 are two clamping screws or bolts for clampingthetube 3 between the plates, and 5 is an electrode adjustably carriedin the plate 1 and extending centrally into the tube.

The plate 2 is provided with a central aperture 6 and is split to form aclam ing collar, a clamping screw '7 being provided to clamp the openends together tightly upon the end of the spark-plug. The plates 1 and 2are preferably recessed to form seats for the ends of the tube 3.

The electrode 5 is screwthreaded and bears upon its outer end suitablemeans such as the screw nuts 8 for connection with an electricconductor.

In practice the parts being constructed and arranged as shown anddescribed, the device is attached to the outer end of the spark plug insuch manner as to bring the outer end of the central electrode thereofwithin the tube into axial line with the electrode 5 and by adjustin thelatter the proper spark gap is obtainedli The device is simple andinexpensive and in addition to the advantage of having a visible spark Ihave found that the hotter spark due to the added spark gap in theigniting circuit greatly reduces spark trouble such as arising from thedeposition of oil on the terminals of the spark plug.

The device may be readily modified to suit spark plugs of differentconstructions as by changing the size of the aperture (3 or any otherknown means for-attaching the device to a spark plug however, may beprovided all of which I consider to be within the scope of my invention.

\Vliat- I claim as my invention is 1. Anattachment to a spark plugcomprising a pair of opposed plates of insulating material provided withannular grooves facing each other, a glass tube interposed between andhaving its ends seated in said grooves, clamping means for forcing oneplate toward the other, an electrode in one of the plates, and meanscarried by the other plate for clamping the same to a spark plug.

2. An attachment to a spark plug comprising a pair of opposed plates ofinsulating material provided with annular grooves, a lass tubeinterposed between the plates and having its ends seated in saidgrooves, means for drawing the plates together to clamp the tube, anelectrode in one plate, and means for clamping the other plate to aspark plug.

In testimony whereof I aflix my signature in presence of two witnesses.

HENRY C. I-IEMMETER.

VV'itnesses C. R. STICKNEY, A. M. SIIAN Non.

